The total reproducibility covering all three methods (SR) for the WHO PCBs was 0,25 pg TEQ/m3 based on measurements at a municipal waste incinerator over an extreme low concentration range from 0,19 pg TEQ/m3 to 0,41 pg TEQ/m3. The corresponding total reproducibility was 6,8 ng/m3 for the sum of the six marker PCBs over a concentration range from 4,4 ng/m3 to 11 ng/m3.
The between laboratory variances for the chemical analysis for the standard solutions and the extract were all below 11 %, the corresponding within laboratory variance was below 5 %. For the fly ash samples the between laboratory variance for the WHO PCBs was 12 % and 16 % for the low and high level sample respectively, the corresponding within laboratory variance was 4 % and 8 %. The variance for the sum of the marker PCBs were significantly higher both between and within the laboratories varied from 17 % to 47 %.
This result is surprising because the analysis of WHO TEF assigned PCBs is generally assumed to be more difficult.
These concentrations were very close to the LOD values based on the field blanks for the three methods which ranged from 0,11 pg TEQ/m3 to 0,57 pg TEQ/m3 for the WHO PCBs and 1,3 ng/m3 to 14 ng/m3 for the marker PCBs. Corresponding LOQ values based on the field blanks varied from 0,20 pg/m3 to 1,37 pg/m3 for the WHO PCBs and from 1,7 ng/m3 to 33 ng/m3 for the marker PCBs,
The levels in the field blank samples were at least two orders of magnitude below the EU limit value for PCDD/PCDF, used in the absence of a limit value for PCBs (see 10.3).
Recoveries of the isotope labelled standards were in good agreement with the requirements given in 10.4, d).
The absolute amount of breakthrough at levels just above the detection limit and field blank levels were at least two orders of magnitude below the EU limit for all three methods. At the high concentrations of a shredder plant (0,29 ng WHO-TEQPCB/m3 to 0,94 ng WHO-TEQPCB/m3 respectively 3 500 ng/m3 to 26 100 ng/m3 for the marker PCBs) the breakthrough was below 0,6 % for the WHO-TEQPCB and below 6 % for the sum of the marker PCBs for the filter/condenser method.
A compilation of the validation results is given in Table 5, all further details and tables are given in Annex C.
Table 5 — Compilation of the validation measurement results WHO-TEQPCB
pg/m3
Marker PCBs ng/m3 Validation at the municipal waste
incinerator
Concentration range 0,19 to 0,41 4,4 to 11
Total reproducibility covering all three
methods (SR) 0,25 6,8
LOD 0,11 to 0,57 1,3 to 14
LOQ 0,20 to 1,37 1,7 to 33
Field blanks 0,07 to 0,47 0,97 to 8,55
Validation at the shredder plant
Concentration range 290 to 940 3 500 to 26 100
Break through 0,6 % 6 %
Field blanks 1,1 to 1,2 5,8 to 5,9
13 Interferences (informative)
Interferences are most likely to occur from compounds that have similar chemical and physical properties.
Although clean-up methods are designed to remove very effectively the most common chemicals from the extract, some interferences remain. These can be divided into the following four types:
a) Interferences by ions of similar mass that cannot be eliminated by the resolution of the mass spectrometer. These are above all the PCDDs if they could not have been removed from the dioxin-like PCBs during the clean-up.
b) Interferences by fragmentation products of chlorine loss(es) of higher chlorinated PCBs. These interferences are difficult to eliminate because the initiating compounds are part of the compounds to be analysed and therefore belong to the sample. If the signal coming from those higher chlorinated PCBs cannot be reliably separated from the signals of interest, the quantification limits have to be adapted.
These concentrations were very close to the LOD values based on the field blanks for the three methods which ranged from 0,11 pg TEQ/m3 to 0,57 pg TEQ/m3 for the WHO PCBs and 1,3 ng/m3 to 14 ng/m3 for the marker PCBs. Corresponding LOQ values based on the field blanks varied from 0,20 pg/m3 to 1,37 pg/m3 for the WHO PCBs and from 1,7 ng/m3 to 33 ng/m3 for the marker PCBs,
The levels in the field blank samples were at least two orders of magnitude below the EU limit value for PCDD/PCDF, used in the absence of a limit value for PCBs (see 10.3).
Recoveries of the isotope labelled standards were in good agreement with the requirements given in 10.4, d).
The absolute amount of breakthrough at levels just above the detection limit and field blank levels were at least two orders of magnitude below the EU limit for all three methods. At the high concentrations of a shredder plant (0,29 ng WHO-TEQPCB/m3 to 0,94 ng WHO-TEQPCB/m3 respectively 3 500 ng/m3 to 26 100 ng/m3 for the marker PCBs) the breakthrough was below 0,6 % for the WHO-TEQPCB and below 6 % for the sum of the marker PCBs for the filter/condenser method.
A compilation of the validation results is given in Table 5, all further details and tables are given in Annex C.
Table 5 — Compilation of the validation measurement results WHO-TEQPCB
pg/m3
Marker PCBs ng/m3 Validation at the municipal waste
incinerator
Concentration range 0,19 to 0,41 4,4 to 11
Total reproducibility covering all three
methods (SR) 0,25 6,8
LOD 0,11 to 0,57 1,3 to 14
LOQ 0,20 to 1,37 1,7 to 33
Field blanks 0,07 to 0,47 0,97 to 8,55
Validation at the shredder plant
Concentration range 290 to 940 3 500 to 26 100
Break through 0,6 % 6 %
Field blanks 1,1 to 1,2 5,8 to 5,9
13 Interferences (informative)
Interferences are most likely to occur from compounds that have similar chemical and physical properties.
Although clean-up methods are designed to remove very effectively the most common chemicals from the extract, some interferences remain. These can be divided into the following four types:
a) Interferences by ions of similar mass that cannot be eliminated by the resolution of the mass spectrometer. These are above all the PCDDs if they could not have been removed from the dioxin-like PCBs during the clean-up.
b) Interferences by fragmentation products of chlorine loss(es) of higher chlorinated PCBs. These interferences are difficult to eliminate because the initiating compounds are part of the compounds to be analysed and therefore belong to the sample. If the signal coming from those higher chlorinated PCBs cannot be reliably separated from the signals of interest, the quantification limits have to be adapted.
NOTE Special care should be taken with respect to interferences of PCB 126 (see Annex E, Figure E.3). This interference can be avoided by separation of non-ortho PCBs from the other PCBs as described in Annex B.
c) Interferences by ions that overlap with the lock mass and therefore shift the mass calibration. By choice of another lock mass this interference can be avoided.
d) Interferences by big amounts of sample matrix that lower the ion yield during ionisation which causes a significant decrease of sensitivity. This effect is particularly strong with electronegative compounds such as phthalates. Interferences like this can be removed by additional and/or repeated clean-up steps.
Some examples for interferences mentioned above are given in Annex E.
Annex A (informative)
Toxicity and toxic equivalency
The PCBs listed in the WHO proposal of 1997 are considered to show comparable toxicity as 2,3,7,8-chlorine- substituted PCDDs/PCDFs. Some general information on the toxicity effect mechanism and the toxicity equivalency system (TEQ-system) is given in EN 1948-1:2006, Annex A.
The most recent TEQ scheme, developed by the World Health Organisation (WHO) and the International Programme on Chemical Safety (IPCS) standardises the toxicity of 17 PCDD and PCDF congeners and includes for the first time, 12 dioxin-like PCBs. It reflects the present knowledge about toxic effects of PCDD/PCDFs and dioxin-like PCBs.
The WHO-TEQ approach is linked to a WHO recommendation concerning a Tolerable Daily Intake (TDI) for humans of 1 pg to 4 pg Total WHO-TEQ/kg body weight which should not be exceeded. The TDI was recommended on the basis of health effects (including developmental, reproductive, hormonal, immune system and neuro-behavioural effects), dose-response relationships and quantitative risk extrapolation.
Table A.1 — WHO Toxic Equivalency Factors (WHO-TEFs) for mammals [9; 10] and International Toxic Equivalency Factors (I-TEFs) [11] a
Congener I-TEF 1988 [11] WHO-TEF 1998 [9] WHO-TEF 2006
[10]
Chlorinated dibenzo-p-
dioxins
2,3,7,8-TCDD 1 1 1
1,2,3,7,8-PeCDD 0,5 1 1
1,2,3,4,7,8-HxCDD 0,1 0,1 0,1
1,2,3,6,7,8-HxCDD 0,1 0,1 0,1
1,2,3,7,8,9-HxCDD 0,1 0,1 0,1
1,2,3,4,6,7,8-HpCDD 0,01 0,01 0,01
OCDD 0,001 0,000 1 0,000 3
Chlorinated
dibenzofurans
2,3,7,8-TCDF 0,1 0,1 0,1
1,2,3,7,8-PeCDF 0,05 0,05 0,03
2,3,4,7,8-PeCDF 0,5 0,5 0,3
1,2,3,4,7,8-HxCDF 0,1 0,1 0,1
1,2,3,6,7,8-HxCDF 0,1 0,1 0,1
1,2,3,7,8,9-HxCDF 0,1 0,1 0,1
2,3,4,6,7,8-HxCDF 0,1 0,1 0,1
1,2,3,4,6,7,8-HpCDF 0,01 0,01 0,01
1,2,3,4,7,8,9-HpCDF 0,01 0,01 0,01
Annex A (informative)
Toxicity and toxic equivalency
The PCBs listed in the WHO proposal of 1997 are considered to show comparable toxicity as 2,3,7,8-chlorine- substituted PCDDs/PCDFs. Some general information on the toxicity effect mechanism and the toxicity equivalency system (TEQ-system) is given in EN 1948-1:2006, Annex A.
The most recent TEQ scheme, developed by the World Health Organisation (WHO) and the International Programme on Chemical Safety (IPCS) standardises the toxicity of 17 PCDD and PCDF congeners and includes for the first time, 12 dioxin-like PCBs. It reflects the present knowledge about toxic effects of PCDD/PCDFs and dioxin-like PCBs.
The WHO-TEQ approach is linked to a WHO recommendation concerning a Tolerable Daily Intake (TDI) for humans of 1 pg to 4 pg Total WHO-TEQ/kg body weight which should not be exceeded. The TDI was recommended on the basis of health effects (including developmental, reproductive, hormonal, immune system and neuro-behavioural effects), dose-response relationships and quantitative risk extrapolation.
Table A.1 — WHO Toxic Equivalency Factors (WHO-TEFs) for mammals [9; 10] and International Toxic Equivalency Factors (I-TEFs) [11] a
Congener I-TEF 1988 [11] WHO-TEF 1998 [9] WHO-TEF 2006
[10]
Chlorinated dibenzo-p-
dioxins
2,3,7,8-TCDD 1 1 1
1,2,3,7,8-PeCDD 0,5 1 1
1,2,3,4,7,8-HxCDD 0,1 0,1 0,1
1,2,3,6,7,8-HxCDD 0,1 0,1 0,1
1,2,3,7,8,9-HxCDD 0,1 0,1 0,1
1,2,3,4,6,7,8-HpCDD 0,01 0,01 0,01
OCDD 0,001 0,000 1 0,000 3
Chlorinated
dibenzofurans
2,3,7,8-TCDF 0,1 0,1 0,1
1,2,3,7,8-PeCDF 0,05 0,05 0,03
2,3,4,7,8-PeCDF 0,5 0,5 0,3
1,2,3,4,7,8-HxCDF 0,1 0,1 0,1
1,2,3,6,7,8-HxCDF 0,1 0,1 0,1
1,2,3,7,8,9-HxCDF 0,1 0,1 0,1
2,3,4,6,7,8-HxCDF 0,1 0,1 0,1
1,2,3,4,6,7,8-HpCDF 0,01 0,01 0,01
1,2,3,4,7,8,9-HpCDF 0,01 0,01 0,01
OCDF 0,001 0,000 1 0,000 3
Non-ortho substituted
PCBs
3,3’,4,4’-TeCB(77) - 0,000 1 0,000 1
3,4,4’,5-TeCB (81) - 0,000 1 0,000 3
3,3’,4,4’,5-PeCB (126) - 0,1 0,1
3,3’,4,4’,5,5’-HxCB (169) - 0,01 0,03
Mono-ortho substituted
PCBs
2,3,3’,4,4’-PeCB (105) - 0,000 1 0,000 03
2,3,4,4’,5-PeCB (114) - 0,000 5 0,000 03
2,3’,4,4’,5-PeCB (118) - 0,000 1 0,000 03
2’,3,4,4’,5-PeCB (123) - 0,000 1 0,000 03
2,3,3’,4,4’,5-HxCB (156) - 0,000 5 0,000 03
2,3,3’,4,4’,5’-HxCB (157) - 0,000 5 0,000 03
2,3’,4,4’,5,5’-HxCB (167) - 0,000 01 0,000 03
2,3,3’,4,4’,5,5’-HpCB
(189) - 0,000 1 0,000 03
a Numbers in bold indicate changes in toxic equivalency factors.
Annex B (informative)
Examples of extraction and clean-up procedures